ALL shapes and sizes are signing up for our onesie fun day – from hulking great rugby players to toddler TV stars.

We launched the first-ever National Onesie Day last week and the response has been phenomenal.

Bank workers, shop assistants, secretaries and mechanics have all pledged to take part as well as pupils at high schools, primaries and nurseries – as everyone gets ready for the comfiest fundraising event ever.

Wear your onesie wherever you are on Friday, May 17 – and donate a £1 to our Centenary Fund appeal to raise £1million for charity.

Sunday Mail Centenary Fund (Photo: Sunday Mail)

We’re marking the 100th birthday of the Sunday Mail in 2014 by uniting the country in a massive fundraising drive – and it’s already capturing the imagination of young and old, big and small.

Ex-Taggart star Colin McCredie, 40, was persuaded into a giant babygro by his two young daughters – Betsy, four and Maisie, seven – who are dedicated fans of their onesies.

He said: “I am delighted to be backing the Centenary Fund celebrating 100 years of the paper and helping to raise money. It is brilliant that the Sunday Mail are supporting so many charities close to my heart.”

Devoted dad Colin has become a favourite on children’s TV since appearing in the hit CBeebies show Woolly & Tig along with his little girls. Betsy plays his on-screen daughter Tig while Maisie narrates the programme.

Colin is delighted that several of the 17 Scottish charities chosen to benefit from our appeal are children’s organisations.

He added: “As a dad, I’m proud to be supporting charities like Calum’s Cabin, Children First and CHAS. It’s a fantastic idea.’

Betsy and Maisie look cute as buttons in their onesies, but it’s harder to look good in a romper suit when you are an 18-stone rugby star.

Edinburgh Rugby players David Denton and Ritchie Rees don onesies to support National Onesie Day (Photo: Alan Simpson)

But to prove that size is no barrier to taking part, we came to the rescue of Edinburgh Rugby players David Denton and Richie Rees, who turned superheroes to raise money for our fund. We found suits to fit them. Scotland No8 David, donned a Superman onesie while Welsh scrum-half Richie squeezed into a fetching Batman ensemble.

After a training session at Murrayfield with their team-mates, the lads proved what good sports they are.

David, 23, said: “I don’t have a onesie at home but I’ll definitely be wearing this one on May 17 and long after that.

“It’s a great cause and if we can raise a bit of money by having fun, that’s even better.”

Richie, 29, cousin of Gavin and Stacey star Joanna Page, added: “I love dressing up but don’t have a onesie. This is the first time I’ve worn one and it fits me like a glove.

“Everyone has had a great laugh watching us prance about in them but we hope everyone will wear their onesies to support the Sunday Mail’s National Onesie Day.”